Members pekelnik Posted June 2, 2017 Members Share Posted June 2, 2017 If it isn't the fuse (left bottom when you remove the rear panel), check the white block grid resistors, they will have darkened the PCB a bit, but shouldn't be too baked, and then check the coupling caps for leakage. They should not have any material trying to get out where the leads are coming in. Link to comment Share on other sites More sharing options...
Members RaVenCAD Posted June 2, 2017 Author Members Share Posted June 2, 2017 I looked closely at the board and all the components and I saw nothing unusual. I sniffed it too, and didn't smell anything fried. Link to comment Share on other sites More sharing options...
Members Bucksstudent Posted June 2, 2017 Members Share Posted June 2, 2017 But did it smell grilled? I like my amp to smell like Original recipe. Link to comment Share on other sites More sharing options...
Members onelife Posted June 2, 2017 Members Share Posted June 2, 2017 ... For working on amps. I usually drain the caps by touching the leads with an insulated handle screwdriver with shaft touching the metal amp chassis at the same time. Hopefully, this won't kill me... I found that the best way to discharge the power supply is by grounding pin 1 of V1 with a jumper cable (with the power disconnected from the amplifier of course). This drains the charge from the filter capacitors through a few resistors - which is a more gentle approach. Link to comment Share on other sites More sharing options...
Members RaVenCAD Posted June 2, 2017 Author Members Share Posted June 2, 2017 Grilled? You on a diet? Pssh! I poured a bottle of hot sauce in it... Link to comment Share on other sites More sharing options...
Members RaVenCAD Posted June 2, 2017 Author Members Share Posted June 2, 2017 The inverter tube did the trick! My Hot Rod rides again.. Still confused why my power tubes would test bad if it wasn't related to them. Maybe they were just old and worn out anyway? That's how I'm rationalizing spending $65 I probably didn't need to spend. Link to comment Share on other sites More sharing options...
Members thatsbunk Posted June 2, 2017 Members Share Posted June 2, 2017 See my post from the other day on this thread. Maybe that was the tube my friend swapped to get me up & running again. I knew it was a 12ax7 & just assumed it was the preamp tube... Link to comment Share on other sites More sharing options...
Moderators Ratae Corieltauvorum Posted June 6, 2017 Moderators Share Posted June 6, 2017 RC, I still got both Fender schematic for my HRD III. I'll get em copied up and mail a set to you. Link to comment Share on other sites More sharing options...
Moderators Ratae Corieltauvorum Posted June 6, 2017 Moderators Share Posted June 6, 2017 Well, if the schematics are A3 or less then I can scan then straight to your email address, from today....thanks to Sharp commercial printing and scanning services Link to comment Share on other sites More sharing options...
Members WRGKMC Posted June 6, 2017 Members Share Posted June 6, 2017 Great news. Thinking the problem through and working from the most likely to the least likely is always the best path to take when troubleshooting. It usually saves time and money. You always want to consider why this happened to begin with so you aren't destined to repeat the same problem again. Blown power tubes and inverters usually spells two possibilities besides it just being a freak occurrence, of premature failure which are actually are very rare. The first is you used the tubes for far too long. I'd cut the time you went with the current set of tubes in half. Combo's typically get half the life or less then a separate head because of vibration. The tubes literally vibrate themselves to death long before they cook themselves. They normally become microphonic and you can actually hear either odd ringing or static before they short. If you got two years out of the tubes, change them at half life. Tubes are cheap and easy to replace. The other possibility would be your speaker impedance is too high. If you use an extension speaker make sure its within the limits of the amp. I believe the amp runs at 8 ohms and can run a 4 ohm minimum with an 8 ohm extension in parallel. If you don't use the internal speaker and use a 16 ohm cab (or the internal speaker was swapped for a 16 ohm) its will cook the power tubes in a short time. I suspect its just the age of the tubes vs the vibration in your case. Link to comment Share on other sites More sharing options...
Members RaVenCAD Posted June 8, 2017 Author Members Share Posted June 8, 2017 I appreciate the offer, but turns out it was something simple and cheap. My kind of fix.. I prefer not messing around inside a tube amp cuz I'm allergic to electrocution. Link to comment Share on other sites More sharing options...
Members RaVenCAD Posted June 8, 2017 Author Members Share Posted June 8, 2017 That was the one. On the III, they call it VX3. Link to comment Share on other sites More sharing options...
Members RaVenCAD Posted June 8, 2017 Author Members Share Posted June 8, 2017 Well, I bought this amp used, so I have no idea how many hours it had on it. I know I've put less than 20 on it personally. He could have used it for months or even years. It had a ringing in it since the day I got it. It's gone now, and yes I turned it all the way up to see if it was there. That's damn brutal with a Hot Rod! It's running the stock speaker and no cabinet, so that wouldn't be in. I'm thinking it was just old and needed new tubes. I'll probably go ahead and replace the two preamp tubes as well, just to have it done with. Link to comment Share on other sites More sharing options...
Moderators Ratae Corieltauvorum Posted June 8, 2017 Moderators Share Posted June 8, 2017 Cool, so a phase inverter eh. The next time it goes, try a balanced GT ECC83S, it gives the most even drive to the output valves. Link to comment Share on other sites More sharing options...
Moderators Ratae Corieltauvorum Posted June 8, 2017 Moderators Share Posted June 8, 2017 There appears to be about 5 less than perfect features on the HRD/HRD III [video=youtube;30Hm8jAQSgI] Link to comment Share on other sites More sharing options...
Members WRGKMC Posted June 8, 2017 Members Share Posted June 8, 2017 Inverters are usually 12AT7's in Fenders but they are interchangeable. The 12AX7 produces more gain. Link to comment Share on other sites More sharing options...
Members GAS Man Posted June 9, 2017 Members Share Posted June 9, 2017 Remember that Fender amps have 5 year warranties. So unless it's tubes, you may be covered, assuming you're < 5 years. Link to comment Share on other sites More sharing options...
Members RaVenCAD Posted June 10, 2017 Author Members Share Posted June 10, 2017 I used a common 12AX7 / ECC83 and I dig the sound I'm getting. I'm not much of a tweaker when it comes to the tubes. As long as I can get a smooth, creamy clean tone, I'm a happy guy. Then I add the dirt with my pedals. I do intend to swap the first tube in the preamp with a 12AT7 though. Sposta be a magic bullet for controlling the volume and headroom for the Hot Rod. Link to comment Share on other sites More sharing options...
Members onelife Posted June 10, 2017 Members Share Posted June 10, 2017 12AX7 in the HRD Link to comment Share on other sites More sharing options...
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